Recently, liquid crystal substances have made startling progress in the application thereof, such as quick responsive displays utilizing the electrooptical characteristics thereof, etc. These liquid crystal substances are almost composed of organic compounds having a relatively low molecular weight.
On the other hand, high molecular liquid crystals which are high molecular substances capable of forming liquid crystal phase have now been actively investigated.
That is, since the Elliot et al's discovery in 1950 that a chloroform solution of poly(.gamma.-benzyl-L-glutamate) showed a double refractivity in the course of the evaporation of the solvent [Discussion of Faraday Society, 9, 246, (1950)], which became the beginning of the investigation of high molecular liquid crystals, the investigation on such high molecular liquid crystals has been continued.
In particular, since the discovery of that high strength and high elastic fibers could be spun from a liquid crystal orientation solution of poly(p-phenyleneterephthalamide) by E. I. Du Pont de Nemours and Company in 1968 (British Pat. No. 1,283,064), high molecular liquid crystals have been actively investigated aiming at the development of high strength and high elastic fibers.
The aforesaid high molecular liquid crystals are all lyotropic liquid crystals. On the other hand, thermotropic high molecular liquid crystals have begun to appear since the 1970's as seen in the Jackson et al's discovery of the thermotropic liquid crystal characteristics of a random copolymer of poly(ethylene terephthalate) and poly(p-oxybenzoyl) [Journal of Polymer Science, Polymer Chemistry Edition, 14, 2093, (1976)], etc. Thus, thermotropic high molecular liquid crystals have been actively investigated aiming at the development of fibers having dynamic characteristics of high performance by melt spinning.
In any cases, the application of high molecular liquid crystals as functional materials is expected utilizing the advantage as high molecular substances capable of forming films, fibers, etc., and the advantage capable of forming liquid crystal phase.
In particular, the investigations for not only the dynamic characteristics of high molecular liquid crystals but also the development of new characteristics and the application thereof have been desired.